If I create a textbook using iBooks Author and then decide to made
it freely available to the world (à la Khan Academy) I can
do that without any restriction. Simple click ‘Export’ within
iBook Author and the resulting file can be distributed by any
means I choose and then loaded in iBooks. The mind boggles at what
things may come out of this.

All Apple is doing with this restriction is saying that if you
directly profit from this free tool and platform that we have
created, then we deserve our cut. Which seems entirely fair to me.

I’ve been pondering this, and I’m thinking Apple’s perspective is about two things. First, it’s about Smith’s argument above. You don’t get to use this free tool to produce books that you sell directly to customers, circumventing Apple’s store. Think about the textbook business, where a publisher might sell thousands of copies of the same book to each school district. This isn’t just about selling iPads — Apple wants its 30 percent.

Second, it’s about not wanting iBooks Author to serve as an authoring tool for competing bookstores like Amazon’s or Google’s. The output of iBooks Author is, as far as I can tell, HTML5 — pretty much ePub 3 with whatever nonstandard liberties Apple saw fit to take in order to achieve the results they wanted. It’s not a standard format in the sense of following a spec from a standards body like the W3C, but it’s just HTML5 rendered by WebKit — not a binary blob tied to iOS or Cocoa. It may not be easy, but I don’t think it would be that much work for anyone else with an ePub reader that’s based on WebKit to add support for these iBooks textbooks. Apple is saying, “Fuck that, unless you’re giving it away for free.”

With these licensing restrictions, Apple is attempting to get the lock-in benefits of a proprietary file format without the proprietary file format.